This invention relates to monolithic microwave integrated circuits and in particular to GaAs isolators and circulators for such systems.
In many microwave systems, nonreciprocal components such as isolators and circulators are needed for avoiding interaction between various ports of a system. In conventional microwave circuits and hybrid microwave integrated circuits, a ferrite material is used to form these components. These components can also be fabricated on a gallium arsenide (GaAs) substrate by using ferrite disks and permanent magnets. However, this technique results in excessively large size and weight and is not compatible with monolithic microwave integrated circuit (MMIC) technology.